import pygame

class Ship():

  def __init__(self,screen):
    """初始化飞船及其位置"""
    self.screen = screen

    #加载飞船图像并获取其外接矩形
    self.image = pygame.image.load('images/ship.bmp')
    self.rect = self.image.get_rect()
    self.screen_rect = screen.get_rect()

    #将飞船放在屏幕底部中央
    self.rect.centerx = self.screen_rect.centerx
    self.rect.bottom = self.screen_rect.bottom

    #移动标志
    self.moving_right = False

  def update(self):
    #根据移动标志调整飞船位置
    if self.moving_right:
      self.rect.centerx +=1

  def blitme(self):
    """在指定位置绘制飞船"""
    self.screen.blit(self.image,self.rect)